Page:Popular Science Monthly Volume 47.djvu/84

76 receive that training which brings them under the complete control of the will; that the perceptive organs be habituated to convey clear and accurate impressions to the brain.

To the wholesome use of the mind it is essential that the impressions coming thereto be perceived in their exact relation, so that nerve and muscle may be directed to most efficient result; its development means the more extended and the more complex correlation of an increasing number and variety of impressions.

The highest moral development is attained through the increasing and constantly more refined perception of that conduct which contributes to the highest good of one's self and others, and action in accordance therewith.

Here arises the fact that the physical and mental structures of different individuals are of greatly varying capacities. An amount of physical exertion that serves only as wholesome exercise to one man might ruin another of less sturdy structure. The amount of mental exertion upon which one brain thrives and develops would cause another pain, and would be utterly impossible for yet another. Different impressions coming under different conditions, through bodies of different fiber, to brains of different caliber, have, together with the mold given by differing influences of heredity, produced that difference of characteristics in different individuals that is so incalculable that it is accepted as a truism that no two persons are exactly alike. It is obvious, therefore, that no one can contribute to the totality of effort in greater degree or in kind other than his physical and mental structure and characteristics will permit. The laborer on the embankment has the muscle wherewith to use the pick and shovel, but ordinarily is incapable of that co-ordination of hand and brain which would enable him to use tools of a higher class. The blacksmith has that adjustment of brain and muscle which enables him to bend and shape the bars of iron. Through the ascending ranks of artisans this adjustment of brain and muscle becomes more delicate, reaching a rare degree of precision in, for example, the optician who grinds and shapes the glasses for spectacles, microscope, and telescope. The clerk who keeps journal and ledger, or who prepares deeds and mortgages, has that control of the hand and that mental development which suffice for this work. Neither laborer, blacksmith, optician, nor clerk could perform the work accomplished by the other; but each, by giving to others the benefit of effort of which he is physically and mentally capable, receives that which enables him to obtain the food, shelter, and clothing necessary to his maintenance.

And it is through work of body and brain that yet higher result is achieved. The blacksmith's son, compelled to contribute early in life to the support of himself, his brothers and sisters,